X-Message-Number: 26057 Date: Tue, 19 Apr 2005 09:27:49 -0400 From: Thomas Donaldson <> Subject: To Daniel Crevier, again: For Daniel Crevier, again: If you read my comments again you will note that I am not arguing against digital computers at all. I am arguing against the possibility of making a brain simulation using time-sharing, a quite different problem. And if we take our time-sharing brain simulation into the real world, it will fail, no doubt with a delay (which I personally suspect won't be very long) depending on just how parallel the brain simulation is. And of course for a computer to be a parallel computer, you require physically separate computers working simultaneously. A simulated parallel computer just doesn't do that. If, however, we start thinking about many analog computers all working in parallel, you do start to get something. You'll need a lot more, but if we form our memories from the way in which are neurons are connected then analog computers (imitating in analog the workings of neurons) might actually be designed to do exactly that. A big step, but not the whole distance, towards a real conscious computer-brain. It looks much easier to make analog devices (even from living cells) able to grow dendrites and axons, and new synapses, and even able to produce new neurons, than we could from any digital device. And if we try to implement not only a brain, but a person in a simulated computer world, we get into lots of problems, as Bob Ettinger has briefly discussed and as I described in my last message to you. Incidentally, the problem with predicting the weather is deeper than our choice of algorithms and computers to do so. By its nature, the weather is unstable. Small variations in a solution blow up with time. This is not a problem solvable by either digital or analog computers except (as I said) for a finite future time span, and the calculations can only do that if they're far more accurate than the final result during that time. Of course, no matter how accurate you make your calculations, with time your solution will cease to be accurate at all. Best wishes and long long life for all, Thomas Donaldson Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=26057